I already solved my problems. You can view the new forum here http://grow-together.de/forum/.
@reverendgeneral What kind of line do you need? Maybe you add an tag manually. For better styling options I divided the “loop-forums.php” in two parts.
Thank you very much for your theme, it’s very nice and a good start to work with bbPress.
I have two issues, I try to solve, maybe someone could help me.
So, in the Forums-Listing, if there is an empty forum under a category, he displays the category name as the last post instead of “No Posts”.
The second one is, that he don’t stick, sticky posts. Superstickys work very well, but the sticky ones not.
Greetings